1. Field of the Invention
The present invention relates in general to a navigation system, more particularly, to a method for searching a return path of a moving object (e.g., vehicle). Thus although the moving object deviates from its driving path and takes a different path, it can always return on the original driving path from a deviation point.
2. Discussion of the Background Art
In general, a navigation system detects a present position of a moving object on the basis of signals received from a plurality of GPS (Global Positioning System) satellites belonging to the US military GPS system, and signals detected by a plurality of sensors mounted on the moving object, including a gyro that detects traveling direction and a speed sensor that detects traveling speed, for example, and matches the detected present position of the moving object on a map data.
Also, using the present position information matched on the map data, the navigation system searches a driving path from the present position to a destination, and driving the moving object to the destination, along the searched driving path.
Particularly, to guide the moving object to the driving path originally set, the navigation system with the path searching and driving functions repeatedly confirms to which direction the moving object is traveling from the present position, and how much distance the moving object has been traveling. When the moving object strays off the driving path, returning the moving object on the original driving path is the most essential part of the path searching and guide functions of the system, to help a driver of the moving object to continue the travel.
When the moving object deviates from the driving path, a related art navigation system with the path searching and guide functions used to research a path from the present position to the destination, and guides the driver of the moving object to follow the researched path.
However, according to the related art system, the driver is not provided with a path connected to the original driving path, but a new driving path. In other words, the original driving path is simply replaced by the researched path.
Moreover, there are occasions when the system cannot search a path again even if the moving object strays off. For example, path searching of the moving object is sometimes done using a particular method. That is, suppose that path searching of the moving object has to be done by accessing to a traffic information center over a communication network However, if the present position of the moving object is in a communication blockage, the path searching cannot be done at this point. The driving path can be searched again only after the moving object is moved to a coverage area.
In addition, when the driver has paid to receive useful information on the original driving path, traffic information (i.e., traffic jam) and road works in progress, for example, the paid information cannot be reused, and the driver has to pay again to know a new driving path and any kind of useful information on the newly found path, only resulting in an increase of expense of travel to the driver.